Ceramic material and method of manufacturing ceramic articles



Patented 1, 1932 f ride, are

UNITED STATES PATENT oar-ice WWI. BOO'I'I, OI mom, ILLUOII, MONO]- TO vnlsrm mind (XII- rm, OORPOBATID, OI m YORK, I. Y, A' CORPORATION O! In You MO AND MOD 0] mUIAO'I'UmG cmnc All! Io Drawlni.

This invention relates to a ceramic mate rial and a method of manufacturing ceramic articles, and more articularly to a ceramic material designed or use in moldingarticles, and to a method of molding articles from such material.

Objects of the invention -are to provide an improved ceramic material for use in molding articles, and to 1provide a method of molding ceramic artic es from such material which may be performed by the use of automatic machinery. a

One embodiment of the invention 'comprises a material including talc and clay or other plastic as its chief ingredients, the materials being intermingled with a temporary bonding material and formed into granules of definite size, which granules are then molded into the desired shape in pressure revent the matenal from adhering to the 'es, the granules, before being introduced into the dies, are coated with a small quantity of a soap such as zinc stearate, which so reduces the tendency of the material to adhere to the dies that the dies remain clean after repeating molding operations, so that the moldin operation may be performed by the use 0 automatic machinery with a minimum of attention on the art of the operator..

e invention will be more fully understood from the following detailed description of a preferred embodiment thereof:

In the manufacture of certain articles having electrical insulating properties, powdered talc and kaolin together with a solution of paraflin and wax in carbon tetrachloound together in a ball mill to form a viscous suspension. The resulting material is then dried to form a hard lastic mass which is then broken up into sma particles. The particles may then be screened .to select therefrom only those of the proper size.

The more fully in the application .of Walter J. Scott, Serial No. 291,948, filed Jul 11, 1928, and the aysiplication of Leon I. g Walter J. cott, Serlal No. 416,488, filed December 26, 1929. In accordance with the process just described is set forth' haw and Application AM January a, mo. lerial Io. 41am.

present invention, the selected articles or granules are then mixed with a ut 0.2 per cent of zinc stearate and the material is gentlytumbled or agitated to cause the zinc stearate to form a thin coating over the granules. The material is then placed in dies and molded under pressure to the desired form, after which it may be baked to the desired hardness and strength.v The soap, being on the outer surface of the granules, contacts with the dies and lubricates them, thereby preventing the material from stickmg to the dies, and has no deleterious efiect on the molded Froduct.

By the use 0 the above described method, the molding operation may be made substantially automatic; thatis, the granular material, coated as above described, may be placed in a hofiper which is moved acrossremoving the excess molding material,'whereupon a male die is forced into the mold cavity to mold the material into the desired shape. After the article has been molded, it may be raised to the surface of the die plate bya knock-out member or othermeans known in the art, whereupon the hopper is again moved across the face of the die plate, moving the molded article into a receptacle positioned alongside of the die, and again filling the mold cavity.

The molded articles formed in accordance with this invention include fewer defective articles since the articles are not injured by sticking to the dies, and the practice of this invention eliminates the necessity for coating the dies with oil or other lubricant, which is partially absorbed by the molding material and weakens the bond between the particles of the molding material, thereby weakening the molded articles. A

In the case of mol material which is in plastic or powdered orm, the sea may be incorporated therein by mixing 6 ingredients together in a mill, the amount of soap being necessarily greater because not may be used are the merely the surfaces are to be coated but*a suficient amount 1s tobe added to permeate the entire mass. Exam les of soaps which um potassium and zinc salts of stearic, oleic an palmitic acids the particular soap chosen bein a matter of cheapness and also of the desire ility of adding water to the material. In the case of material which would be detrimentally affected by the presence of the soap, or in case it is found impracticable to incorporate the soap into the material, the soap, preferably in the form of a solution or suspension in liquid, may be applied directly to the dies,

as by spra 'n or painting.

What is dla imed is: i 1. A material for molding under pressure, comprisinggranular ceramic material, the granules of which are coated with a soap.

2. A material for molding underpressure, comprising granular ceramic material, the granules of which are coated with about 0.2 percent of zinc stearate.

3. A method of manufacturing ceramic articles, comprising forming ceramic material into granules, coating the granules with a small amount of soap, and molding the resulting material under pressure.

4. A method of manufacturing ceramic articles, comprising mixing ceramic material with a temporary binder, moor orating soap into the resulting mixture, an molding the mixture under pressure.

5. A method of manufacturing ceramic articles, comprising mixing talc and kaolin with a wax, incorporating soap into the resulting mixture, and molding the mixture under pressure.

6.-A method of manufacturing ceramic articles, comprising'mixing talc and kaolin with a temporary binder, forming the resulting mixture into granules coating the granules with soap, and mol ding the mixture under pressure.

7. A method of manufacturing ceramic articles, comprising mixing talc and kaolin with parafin, forming the resulting mixture into granules, coating the granules with a small amount of zinc stearate, and molding the mixture under pressure.

8. A method of manufacturing ceramic articles, comprising mixing ceramic material with a temporary binder, forming the resulting mixture into granules, coating the" granules with a small amount of soap, molding the mixture in a die under pressure, and banking the molded article.

In witness whereof, I hereunto subscribe my name this 28 day of December, A. D.

' WALTER J. SCOTT. 

